High on a Pennine moor in April at dawn. This is where the action is, the action Matt Ridley returns to chapter by chapter. He may call himself a “voyeur in thermals” but he is a brilliant observer, up and alert at silly o’clock, watching the shenanigans of a black grouse lek.
In a “lek”, the males of certain species gather throughout the breeding season to display themselves in their extravagant finery. Black grouse strut and jump and gurgle. They cock their white tail feathers, arranged “like a chrysanthemum” and flaunt the red combs on their heads. On an otherwise unremarkable patch of moorland, the display goes on for hours. A lek can contain above 20 males, each in his allotted space. The birds sneeze, a sound like “a can of lager being opened”. There is a lot of “koo-rooing”. Sometimes they fight among themselves. And then in fly the females, a few at a time, brown and dowdy – but choosy. They land at the side to watch, which causes a crescendo of bowing and jumping and flaunting of feathers.
Nature documentaries will still tell you that the males are “competing for dominance” for mating “rights” over “harems”. But Ridley insists they are wrong. He opens every chapter of Birds, Sex & Beauty with visits to the lek – because it’s both a wonder in itself and a major part of his purpose is to argue for “sexual selection” as a force in evolution. Female selection, that is. Ridley insists that here, in black grouse, you will plainly see something that Victorian and even 20th-century evolutionists have struggled to accept (Darwin excepted): female agency. Darwin never witnessed a black grouse lek – had he done so, Ridley suggests, he would have been much more sure of his argument. “Nowhere in the animal kingdom is the autonomy of female agency so clear.” She decides when and with whom. When she has chosen a partner, a blackhen will walk unmolested through the arena to reach her choice and mate with him. Then – that’s it, insofar as the male is concerned: two seconds of congress, the deposition of a sac of sperm. He will play no part in the rearing of his offspring. Immediately he’s back to his displaying. After all, he may have just one chance, one springtime in his life when it all comes together for him and he will be the choice of several females. Many males will expend all their energy and get nought; half never mate in their entire lives. Either way they all end up exhausted. Why do they do it? Because female choice has bred it into them. Forget survival of the fittest, this is survival of the dishiest.
The argument about sexual selection, mate choice, rumbled for a century. Darwin mooted it. Alfred Wallace disagreed, as did Julian Huxley in turn. Other naturalists weighed in. Acute field-work and experimentation followed. Why, they wondered, do some male birds (and butterflies and some species of insect) develop quite ludicrous features, beautiful but useless? Why would a peacock lumber himself with such a burden as that tail? Why do some species “go way beyond the needful into the baroque”? There were learned papers and ornithological experiments, discussions by bearded men about the sexual attraction of men’s beards.
Ridley explains all this history with lucidity and wit. It’s amusing to think that female black grouse, a rather plain bird, may have bred into males features which she fancies but are otherwise useless. But given all males now have them, how does she tell them apart? He explains a lek with a delightful analogy involving a Miss Bennett, and a large number of near-identical Mr Darcys. How is a girl to choose? But the grouse are not quite identical. Ridley’s trained eye and devout watching means he can tell them apart – Wonky Tail from Black Bar from Touching Combs. (Indeed, the book is dedicated to the memory of Wonky Tail. Black grouse don’t live longer than a few years.)
Furthermore, not content with fancy feathers, the hens have over evolutionary time trained the males to corral themselves together to show their wares. It’s permanent now. A blackcock can’t take off his ornaments at the end of the season and hang them in a wardrobe. He is lumbered. “Survival be damned.”
The theory of sexual selection fell into abeyance, only to re-emerge, strangely enough, with the rise of women’s emancipation in the 1950s and 1960s. One begins to envy the females of lekking species, who go about unharrassed. But, one wonders, why would the female of any species breed fancy plumage into her males, rather than, say, basic co-parenting skills? A male red grouse, by contrast, shares the same habitat as black grouse, but will spend months protecting and feeding his mate and offspring, and defending his territory. No bling for him. Red grouse males and females are almost identical. It’s suggested that the movement towards exaggerated features is a “runaway” process. Once it begins, a “taste for beauty causes beauty which causes a taste for beauty”. Where might it all end?
And what of ourselves, the “self-obsessed African ape”, and our own evolution? We have our own beautiful but useless traits. Why do we make art, for example? A boring natural selection process, geared to survival, should have weeded out arty types. But if we admit sexual selection, then “aesthetic admiration of art shades over into sexual attraction towards the artist”. (For male artists maybe. Female artists know it’s untrue for them.) Humour may be a better example. Both human sexes value a sense of humour in the other. It’s little use in the harsh world of natural selection, but factor in “mate choice” and it all becomes explicable. Indeed Ridley, following the evolutionary psychologist Geoffrey Miller, reckons “sexual attractiveness alone can be a sufficient explanation for almost any human mental trait”. That must then include traits such as casual cruelty, greed and power-hunger. What is “mate choice” doing here?
The book is clear and entertaining, uniting natural history writing with science, and arguing hard for “mate choice” as a force in the world. It also acknowledges the sheer tenacity of field ornithologists everywhere and their many experiments, snipping feathers off here and gluing them on there. But lay readers may still struggle to understand why the idea of sexual selection was so contentious. For Matt Ridley anyway, the argument is over: sexual selection accounts for the blue hue of a black grouse, for the song of the lark and the butterfly’s wing. It accounts for our human traits, even our brains. Starting some three million years ago, the human brain underwent rapid expansion. This did not happen to other primates, which survive quite well without. Why? The theory of sexual selection suggests that in aeons past we must just have fancied each other’s braininess, males and females both, and mated accordingly. It became a runaway success. We bred huge brains into ourselves, by ourselves. Our brains are a “baroque” feature all of our own, and “one of sexual selection’s greatest creations” – greater even than the peacock’s tail.
Birds, Sex & Beauty: The Extraordinary Implications of Charles Darwin’s Strangest Idea
Matt Ridley
HarperCollins, 409pp, £25
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[See also: How not to build a nation]
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This article appears in the 19 Mar 2025 issue of the New Statesman, The Golden Age